ENH: Add UNKNOWN type for IMPORTED libraries

When creating an IMPORTED target for a library that has been found on
disk, it may not be known whether the library is STATIC or SHARED.
However, the library may still be linked using the file found from disk.
Use of an IMPORTED target is still important to allow per-configuration
files to be specified for the library.

This change creates an UNKNOWN type for IMPORTED library targets.  The
IMPORTED_LOCATION property (and its per-config equivalents) specifies
the location of the library.  CMake makes no assumptions about the
library that cannot be inferred from the file on disk.  This will help
projects and find-modules import targets found on disk or specified by
the user.

1 files changed, 18 insertions, 2 deletions

diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index caa534f..296e93d 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -30,7 +30,8 @@
 const char* cmTarget::TargetTypeNames[] = {
   "EXECUTABLE", "STATIC_LIBRARY",
   "SHARED_LIBRARY", "MODULE_LIBRARY", "UTILITY", "GLOBAL_TARGET",
-  "INSTALL_FILES", "INSTALL_PROGRAMS", "INSTALL_DIRECTORY"
+  "INSTALL_FILES", "INSTALL_PROGRAMS", "INSTALL_DIRECTORY",
+  "UNKNOWN_LIBRARY"
 };
 
 //----------------------------------------------------------------------------
@@ -277,6 +278,7 @@ void cmTarget::DefineProperties(cmake *cm)
      "For frameworks on OS X this is the location of the library file "
      "symlink just inside the framework folder.  "
      "For DLLs this is the location of the \".dll\" part of the library.  "
+     "For UNKNOWN libraries this is the location of the file to be linked.  "
      "Ignored for non-imported targets.");
 
   cm->DefineProperty
@@ -787,6 +789,16 @@ bool cmTarget::IsExecutableWithExports()
 }
 
 //----------------------------------------------------------------------------
+bool cmTarget::IsLinkable()
+{
+  return (this->GetType() == cmTarget::STATIC_LIBRARY ||
+          this->GetType() == cmTarget::SHARED_LIBRARY ||
+          this->GetType() == cmTarget::MODULE_LIBRARY ||
+          this->GetType() == cmTarget::UNKNOWN_LIBRARY ||
+          this->IsExecutableWithExports());
+}
+
+//----------------------------------------------------------------------------
 bool cmTarget::IsFrameworkOnApple()
 {
   return (this->GetType() == cmTarget::SHARED_LIBRARY &&
@@ -1860,7 +1872,8 @@ const char *cmTarget::GetProperty(const char* prop,
   if(this->GetType() == cmTarget::EXECUTABLE ||
      this->GetType() == cmTarget::STATIC_LIBRARY ||
      this->GetType() == cmTarget::SHARED_LIBRARY ||
-     this->GetType() == cmTarget::MODULE_LIBRARY)
+     this->GetType() == cmTarget::MODULE_LIBRARY ||
+     this->GetType() == cmTarget::UNKNOWN_LIBRARY)
     {
     if(!this->IsImported() && strcmp(prop,"LOCATION") == 0)
       {
@@ -1957,6 +1970,9 @@ const char *cmTarget::GetProperty(const char* prop,
       case cmTarget::INSTALL_DIRECTORY:
         return "INSTALL_DIRECTORY";
         // break; /* unreachable */
+      case cmTarget::UNKNOWN_LIBRARY:
+        return "UNKNOWN_LIBRARY";
+        // break; /* unreachable */
       }
     return 0;
     }